It is widely known that light emitting diode (LED) lamps are more energy efficient than incandescent lamps, and thus there is a growing demand for LED lamps that can directly replace incandescent lamps. Many incandescent lamps are installed with a dimmer that varies the brightness. However, incandescent dimmers cannot be used to dim LED lamps without the risk of operational and equipment problems because of the differing construction between LED lamps and incandescent lamps.
For example, incandescent lamps use a wire filament that is directly connected to a supply voltage. As such, an incandescent dimmer can use low cost components such as triacs (triodes) to switch on the voltage at a variable point of the alternating current (AC) sine wave during the negative and positive halves of the wave. This causes the incandescent lamp filament to receive current for longer or shorter durations, which causes the filament to vary in brightness. The dimmer usually transitions from 100% duty cycle to less than 1% duty cycle, which varies the RMS power delivered to the lamp to adjust the brightness from minimum to maximum.
LED lamps are constructed differently from incandescent lamps. For example, LED lamps include sophisticated electronic components and may need to be supplied with a certain amount of constant power in order to maintain the functional state of the components. In addition, LED lamps may include additional functionality, such as color control, that cannot be manipulated by incandescent dimmers.
Thus, there is a need for an improved control technique for LED lamps to enable efficient dimming operation that is safe for LED circuitry and that enables control of additional LED features, including color control, enhanced monitoring of LED lamp life, and coordinated control of multiple LED lamps associated with one or more dimmers.